Washington -LRB- CNN -RRB- -- House Appropriations Committee Chairman David Obey , a senior member of the congressional Democratic leadership , announced Wednesday that he is not seeking re-election this November .

Obey , 71 , represents Wisconsin 's 7th Congressional District . He was the youngest member of Congress when he was elected to his first of 21 terms in 1969 .

He is the fourth-longest-serving House member , serving behind Democratic Reps. John Dingell and John Conyers , both of Michigan , and Florida Republican Rep. Bill Young .

`` I think that along the way I 've made a difference in the district and the state that I represent , and for the country . But there is a time to stay and a time to go , and this is my time to go , '' Obey said in announcing his decision .

`` Frankly , I hate to do it . There is so much that needs to be done . But even more frankly , I am bone tired , '' he said .

House Speaker Nancy Pelosi praised Obey as a `` transformational figure in the Congress . ''

`` He is a visionary for a better life for the American people and a legislative genius : he has an ability to see around corners , anticipate challenges and opportunities and sustain a fight on behalf of what is right . For nearly a half century , he 's been an indefatigable reformer , '' she said .

Obey said he considered retiring after the 2000 election , but he said he became so angered by the policies of the Bush administration `` that I decided to stick around as long as they were here . ''

He also said that when he was asked in the past if he was contemplating retirement , he would tell reporters he did n't want to retire until Congress passed health care reform .

`` Well , now it has , and I can leave with the knowledge that thanks to Speaker Pelosi and President Obama and so many others , we got the job done . I have n't done all of the big things that I wanted to do when I started out , but I 've done all of the big things that I 'm likely to do , '' he said .

Obey won the 2008 election with 61 percent of the vote .

This term , he was expected to face Republican challenger Sean Duffy , the district attorney of Ashland County . Earlier this year , Time magazine named Duffy as one of 10 GOP contenders capable of providing a Scott Brown-like upset , referring to the Republican 's surprise win in the Massachusetts Senate election .

Duffy also appeared on the sixth season of MTV 's `` The Real World . ''

The National Republican Congressional Committee issued a statement saying Obey was facing `` the race of his life . ''

`` That is why it is understandable that the architect of President Obama 's failed stimulus plan has decided to call it quits . It is ironic that a congressman who became infamously known for his short temper and angry tirades on the House floor , is going out with such a whimper , '' NRCC communications director Ken Spain said in a statement .

The nonpartisan Rothenberg Political Report had characterized the district as `` leaning Democratic . ''

The Democratic Congressional Campaign Committee praised Obey as a `` tireless voice for progress on behalf of his constituents in Wisconsin and middle class families across America '' and disputed the notion that his job was at risk .

`` His success in writing a new code of ethics for the House of Representatives and ensuring passage of our historic health insurance reforms will stand as Chairman Obey 's proud legacy , '' DCCC Chairman Chris Van Hollen said in a statement .

`` Chairman Obey would have won re-election again had he run . We are confident that a Democrat who shares Chairman Obey 's commitment to making progress for Wisconsin 's middle class families will succeed him as the next Representative of Wisconsin 's 7th Congressional District . ''

Obey also expressed confidence that he would have held on to his seat .

`` Let me put it this way -- I have won 25 elections , '' Obey said . `` Does anybody really think I do n't know how to win another one ? Or , for that matter , has anyone ever seen me walk away from a fight in my life ? ''

`` The fact is there is n't a chance of a snowball in Hades of that progressive congressional district electing someone who is a poor imitation of George Bush 's policies on a bad day , '' Obey added to applause .

Obey said he believes the job of a good politician is to be `` used up '' fighting for causes one believes in , and then stepping aside to let someone else carry on the battle .

`` Well today folks , I feel used up , '' he said .

Obey said he was n't sure what he planned to do next , but joked , `` All I do know is that there has to be more to life than explaining the ridiculous accountability-destroying rules of the United States Senate to confused and angry and frustrated constituents . ''

CNN 's Deirdre Walsh contributed to this report

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Rep. David Obey , D-Wisconsin , announced he will not run again after 41 years in House

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Obey disputed GOP claim that he was in danger of losing

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`` There is n't a chance of a snowball in Hades '' for GOP win in his district , Obey says

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Obey is appropriations chairman and was key to passing health care bill